ULM toners have numerous advantages over conventional toners. Most signigicantly, ULM toners melt at very low temperatures thus providing a toner system with relatively minor energy requirements.
Conventional ULM toners frequently comprise both an amorphous and a crystalline resin. However, this combination typically results in poor heat cohesion due to the plastisization of the amorphous resin by the crystalline resin. U.S. Patent Application Publication No. 2009/0220882 describes a toner particle designed to overcome this problem by using a core-shell approach, where the shell comprises only the amorphous resin. However, the toner blocking needs to be further improved due to the protrusion of crystalline material to the toner surface.